The purpose of this study is to investigate a simple, non-destructive method for monitoring the natural frequencies of the railway tracks subjected to the axial loads. In this study, two kinds of methods are used to obtain the relationship of the axial loads and the natural frequencies. One is the numerical method, and another one is the laboratory experimental method. For the numerical studies, two different numerical analysis methods are used, namely the Finite Element Method (FEM) analysis, and the Rayleigh-Ritz method analysis. The laboratory method has two different equipment to collect signals, one is an accelerometer and the other is a microphone sensor. They both are processed by using the dynamic analysis instrument. In order to simply and comprehensively verify the practicality, we consider three simply supported beams, which can be considered as a simplified model of the railway track, with different materials and cross-sections. Through the numerical studies, the critical loads and the natural frequencies of the beams are calculated by using the two methods. The results obtained by using the finite element method show a good agreement with the results obtained by the Rayleigh-Ritz method. Through the experiments, it is proved that the laboratory methods can be used to find the natural frequencies of the beams subjected to the axial loads. The methods used in this study could be put into practical use to simulate and detect the axial load and natural frequency of the railway tracks. With further research, the methods would contribute to development of non-destructive testing methods for the railway tracks.